How to Propagate Hydrangeas Successfully

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With their spectacular and long-lasting summer color, it’s hardly surprising that the hydrangea is one of the most popular garden flowers. The most widely grown hydrangea is the mophead, which comes in either white, pink, or – in very acidic soil – blue. But there are other varieties too, each of which is worth growing space and will reward you with a glorious floral display.

If you have a thriving hydrangea in your garden, you may well wish to have more and be wondering how to avoid the cost of buying more plants! The good news is that you can successfully increase the number of hydrangea plants at home, without any great investment and with just a little work and time.

All hydrangeas can be propagated in the same ways, though some methods are more suited to certain varieties than others. For example, if you have a hydrangea with no low-growing branches, it will be difficult or impossible to use the layering method.

Best Propagating Methods

The most common method to use for propagation purposes of hydrangea shrubs is one of the layering methods. Layering is easy, relatively quick, and will produce an identical flowering plant. 

Hydrangeas can also be propagated successfully by taking and rooting plant cuttings.

Raising hydrangea plants from seed is a much longer process, which requires considerably more time and patience. But if you are looking to create a unique plant, and have the time and willingness to commit, then this may be the way you choose to go. Who knows, you might create an award-winning, unique hydrangea in a few years!

Layering

A straightforward way to propagate hydrangeas is by layering. You can use this method to produce new hydrangea shrubs which will be identical to the parent plant, and it can be used for propagating all types of hydrangeas. However, in practice, it is only a practical choice where there are low-growing branches that can be trained and pegged down into the ground.

This is an ideal method of propagation to choose if you have a gap in the soil between your plants, and you wish to fill it.  

First, just select a healthy and low-growing branch and bend it downwards so that it touches the soil. Find a large stone or something weighty to hold the branch in place or use a plant staple to peg it into the ground. 

Cut off any leaves that are touching the soil. You don’t want to leave them on the stem because they will rot and be prone to spreading infection and/or fungal disease.

Then, just leave it alone! Make sure that the soil doesn’t dry out and check it from time to time to see whether little roots are starting to form in the soil. You will know when the stem has rooted as when you lift the weight or peg from the ground, the branch will stay in place unaided.

Whilst it is attached to the parent plant, the layered hydrangea cutting will continue to receive its nutrients. Once it has developed its roots, it is ready to become independent of the parent plant. At this stage, you can cut the branch off so that its root system will start to develop its source of moisture and nutrients.

Don’t be tempted to move it at this stage though, as you will put the plant under too much stress. Give the newly established cutting a few weeks to recover and grow on a bit first before uprooting it if necessary.

Layering is a successful method used for propagating hydrangea shrubs and is easy too.

Stem Cuttings

This is another method of propagating garden shrubs and is a successful choice for increasing your hydrangea plants.

Some people prefer to take their cuttings in spring when the hydrangea is starting to grow vigorously after the winter.  

Other plantsmen choose the autumn to take the cuttings,  to enable the new plants to grow a stronger root system over the winter months than during the summer period. Both methods can work, so it’s really up to you to choose the best time.

Whenever you choose to take the cuttings, don’t do it in strong sunshine, and don’t leave the cuttings lying around for any longer than necessary before potting them up. 

Cut the stem above a leaf node and if it’s long enough you will be able to make two cuttings from one piece of stem  

Because the hydrangea produces large leaves, it is a good idea to remove most of them, as they will not be able to survive remaining on a rootless plant. You can remove all the leaves along the stem apart from the top two which you should cut in half. When trimming the leaves, try to do it as close to the stem as possible.

Hormone rooting powder is optional. The hydrangea is a shrub that will root easily, but the use of hormone rooting powder will speed up the process. The quicker the cutting starts to develop its root system, the greater the chance of propagation success.

Prepare your pots which should be clean and filled with potting compost mix which is suitable for container-grown shrubs.  

If you choose to use hormone rooting powder, dip the cutting into the powder and shake off the excess.

Using a pencil or thin twig, make a hole in the compost. Carefully place the piece of the stem into the hole, making sure that you don’t rub off the powder as you do so. The cutting needs to be upright in the compost.

Keep the pots outdoors, somewhere that is sheltered and receives some sunshine, but where it is protected from the extreme heat of the afternoon sun. 

Don’t allow the pots to dry out, but equally, you mustn’t overwater.

Resist the temptation to disturb the growing cutting! Although you can tell when the roots are starting to form, it is very easy to break them at this embryonic stage of development. So don’t dig it up to have a look, or pull at the stem!

Once you see new leaves starting to form, you are safe! The cutting has rooted and is growing. Now you can consider transplanting the cutting into its pot and growing it on and look forward to thriving new plants very soon!

Seed

To grow hydrangeas from seed, you need a lot of commitment, some technical knowledge, and plenty of patience. It can be the choice for serious plantsmen who are looking to produce a unique hydrangea shrub. It is exciting to produce a plant with an outcome unknown! Each seed-grown plant will be a new cultivar.

Collecting the seed is less simple than you might think. And considering the size of hydrangea blooms, you will be amazed at how tiny their seeds are!

Wait until the flower head begins to fade and place a paper bag over it. Cut it off the plant, and leave the flower to dry in the bag. This can take anywhere from a few days to a couple of weeks. 

When you can shake the bag and see the seeds falling from the flower, you can harvest them. As already stated, the seeds are so small that they can easily be lost or mistaken for dust. 

Either keep the seeds in a cool place until the spring before sowing or sow them immediately. When sowing hydrangea seeds, use a seed tray filled with potting compost and keep them moist and protected from the cold, wind, and direct sunshine. They shouldn’t dry out. The seeds will usually germinate in a couple of weeks.

Once the seedlings have developed three or four leaves, you can plant them into individual pots. Place the pots in a well-lit and sunny position and keep moist until late spring when you can plant them out. If you are very lucky, the new hydrangea seedlings will produce some blooms from their first year after planting, but you may have to wait until the plant is more mature before flowering.

Division

Most shrubs don’t respond well to being split or divided; the hydrangea however is an exception.  You can divide a large hydrangea shrub in the same way as you would split a perennial flowering plant.

Ideally, if you are dividing your hydrangea, do this in the spring early in the growing season before the leaf buds have opened. If you miss the spring, do it during the fall.

Find a branch that is shooting at the outside of the bush; if it has been growing for more than a couple of years, it will probably have a robust root system at the base. You can cut this up, using a spade. 

Providing the piece of plant you have dug up has roots attached, you have no work to do! Propagation is complete. Simply replant this plant and let it grow on.

It is quite likely that if your hydrangea is a mature bush, there will be several rooted shoots that you can use in this way.  

Even if you don’t find any roots, you can still divide a mature hydrangea plant. Dig around the roots and find a natural place to cut the root ball. This will be somewhere in between where the different stems grow from the roots. You may be able to pull the pieces apart, or may need the assistance of a garden fork to divide the plant cleanly.

Plant the two or more pieces of hydrangea and keep an eye on them in the early stages, making sure they don’t dry out.

Hydroponics

This method of propagation is becoming much more popular nowadays and is used frequently by professional growers.

It is a simple process whereby you start with a small stem cutting which you place in a container of water. Only the stem should be in contact with the water, so remove any leaves or buds that may be submerged. If desired, you can add some liquid or gel hormone rooting powder to the water to encourage quicker rooting of your cutting.

Place the container in a warm, well-lit place, but out of direct sunlight which could burn the plant. 

Using a clear container will enable you to see the base of the stem and observe the progress of the developing roots.

The water should be changed frequently.

Once the roots have formed, you can move the plantlet to its own pot and grow it on.

propagate hydrangeas

Aftercare and Growing On

It’s always encouraging when a seedling or cutting has produced roots and become an independent plant. But it still needs plenty of care during the early stages if it is to develop into a healthy, flowering hydrangea.

The most important thing is to provide growing conditions that reduce the stress on the growing plant.  Keeping it moist, not letting the soil dry out, and protecting it from both cold and excessive heat are probably the most significant factors to consider.

A young plant in the early stages of development does not need fertilizer. It will receive sufficient nutrients from the potting compost in which it is growing. An application of fertilizer will damage, not encourage emergent growth. 

If you have grown your hydrangeas from seed, don’t try to keep them all. Be ruthless and weed out any sprouts that are weaker or not growing as well as the rest.  

Let your baby plants continue to grow in their trays or pots until they visibly outgrow their growing environment. Don’t repot too early, as any move puts stress on a plant, which you want to avoid or at least minimize. 

If you have been raising your new hydrangeas indoors, then they should be hardened off before planting outside. They need to be accustomed to the outdoors gradually. 

Finally, consider where you are going to position the hydrangea plant and remember that although the plant is currently only small, it may grow in both height and spread in just a few years. You don’t want to have to transplant it again in a short time. So plan before you plant!

Frequently Asked Questions

How quickly will my new hydrangea produce blooms?

Hydrangeas grown from cuttings will produce flowers from the first growing season after they have been planted out. Usually, this will be when the cutting is between 18 months and two years old. 

A seed grown hydrangea plant will take longer to flower. It might flower the first season once it is planted out, or it may take a few years to become established before it blooms.  Sometimes, flowers will appear the first year and then not again for a further couple of years. This is because, during the early years, the plant is focussing its energies on developing a healthy plant and root structure.

See more: Why are my hydrangeas not blooming?

What soil do I need for my hydrangeas?

For hydrangea cuttings, you should use compost that is specifically formulated for raising shrubs. Hydrangeas like slightly acidic soil, so any growing medium designed for acid-loving plants such as rhododendrons, azaleas, or camellias is ideal.

What’s the success rate for hydrangea cuttings?

There are too many variables to give a precise figure, but propagating hydrangea plants from stem cuttings is a very successful method of increasing your plant stock. Provided you have given your cuttings the best chance to root, and maintained adequate after-care, there is no reason why you shouldn’t have around 90% success with your plants.